Process for converting petroleum oil



July 7, 1936. w. R. HOWARD PROCESS FOR CONVERTING PETROLEUM OIL Original Filed March 4, 1927 I N VEN TOR.

1/47/1221): 1?. Howard TTORNEY.

Patented July 7, 1936 UNITED STATES PATENT OFFIQE PROCESS FOR CONVERTING PETROLEUM OIL William E. Howard, Washington, D. 0., assignor,

by mesne assignments, to Universal Oil Products Company, Chicago, III., a corporation of Delaware 9 Claims.

This application is a continuation of my former application, Serial No. 172,836, filed March 4, 1927, which latter application is a continuation in part of a previous application, Serial No. 525,- 094, filed December 27, 1921.

This invention relates to a process and apparatus for converting petroleum oil, and refers more particularly to a process in which hydrocarbon oil is converted into lower boiling point fractions which are vaporized and condensed separately as distillate. As a further feature of the invention, the vapors formed during the conversion of the hydrocarbon oil are subjected to a series of dephlegmations and the reflux condensates formed in said dephlegmations are separately retreated under suitable conditions to cause further conversion thereof.

The single figure is a side elevational view of an apparatus which can be used to carry out the process.

- In operation, the oil is introduced from storage through the line I and is charged by means of pump 2 through the line 3, controlled by valve 4, into the heating coil 5 mounted in a furnace 6. The oil in the coil is raised to a temperature at which substantial conversion of the oil is promoted. The hot oil from the still 5 passes through line 1, controlled by valve 8, into reaction chamber 9 in which the greatest part of the conversion takes place. During the conversion, a pressure of the generated vapors is maintained upon the oil in heating coil 5 and reaction chamber'9.

From time to time, or continuously, according to the rate of reaction, the heavier or residuum oil separatedin reaction chamber 9 may be drawn off through the lines I0, controlled by valves II. The reaction chamber 9 is also provided with suitablecleaning man-holes (not shown). The vapors evolved during the conversion pass off from reaction chamber 9 through line I2, convapors which are still uncondensed indephlegmator I! pass oh the top thereof, through line I8, controlled by valve I9, into condensing coil 20, and thence through line 2 I, controlled by valve 22,

into receiver 23, where said vapors are collected as liquid distillate. This receiver is provided with gas and distillate draw-oifs, respectively shown at 24 and 25, and controlled by valves 26 and 21. Referring back to dephlegmator I4, the reflux condensate which is separated out in dephlegmator I4 is drawn off the bottom thereof through line 28, in which may be interposed a hot oil pump 29, controlled by valves 30. The hot oil pump 29 may be by-passed, and the reflux condensate from the dephlegmator I 4 passed through line 3|, controlled by valve 32. The reflux condensate'from line 28 is thence charged through heating coil 33 positioned in a furnace 34. This reflux condensate will be subjected in heating coil 33 to further conversion.

' The furnace 34 can be heated in any suitable manner, and I have shown, for instance, that it can be'heated by the spent combustion gases from furnace 6 in which the oil was originally heated. This can be done by closing damper 35 and opening damper 36, or, if desired, damper 35 can be opened and damper 36 can be closed, and furnace 34 can be'independently heated, for instance, by means of burner 31. The reflux condensate from dephlegmator I4, after being heated to proper temperature in heating coil 33, is discharged into separating chamber 38 and the vapors separated will pass off through line 39 and line 40, controlled by Valve M, and. combining with the vapors from dephlegmator I4 in line I5, they Will be subjected to dephlegmation in the dephlegmator I'I.

If-it is desired to separately collect the vapors formed in the conversion of the reflux condensate from dephlegmator I4, said vapor evolved in chamber 38 can be passed through line 39 and through line 42, controlled'by valve 43 (valve 4I being closed), into dephlegmator 44 in which fractionation of the vapors is efiected in any wellknown manner. The vapors are condensed in dephlegmator 44, passed up through line 45, controlled by valve 46, into'condenser 41, and thence through line 48 into the receiver 49 provided with gas and distillate draw-offs 50 and 5I, controlled by valves 52 and 53.

The portions of the reflux condensate from dephlegmator l4 which have not vaporized in separating chamber 38 after retreatment of said reflux condensate through heating coil 33, are withdrawn from chamber 38 through line 54, controlled by valve 55, and can be evacuated to storage or elsewhere. The reflux condensates separated out in dephlegmator 44 can also be withdrawn therefrom through line 56, controlled by valve 57, and directed to storage or elsewhere. But in a preferred form of operation, the unvaporized portions collected in chamber 38, or the reflux condensate formed in dephlegmator 44, or both, are subjected to further conversion in the manner hereinafter described. The unvaporized oil draw-off line 54 is provided with a branch 58 controlled by valve 59, whereby said unvaporized oil can be directed into line 60. Also, reflux condensate draw-off line 60 is provided with a branch 6| controlled by valve 62, whereby the reflux condensate from dephlegmator 44 can be directed into said line 60. In this manner, the reflux condensate from dephlegmator 44, or the unvaporized oil from expansion chamber 38, or both, are directed to pump 63, controlled by valve 64, and charged through line 55 into a heating coil 66 positioned in a furnace G'l. The pump 63 can be by-passed by means of line 68, controlled by valve 69.

This heating coil 66 is supplied both with the unvaporized products of the conversion of the reflux condensate formed in dephlegmator l4, hereinbefore described, and with the reflux condensate formed in dephlegmator I'l. Referring back to said dephlegmator ll, the reflux condensate formed therein is discharged at the bottom thereof, through line 10 and charged by means of pump ll, controlled by valves 12, through line 13 into heating coil 66. Pump H can be by-passed through line 14, controlled by valve 15.

In the heating coil 66, the condensate returned from dephlegmator l1, and the liquid fractions drawn off from chamber 38, or dephlegmator 44,

or both, are subjected to conditions of tempera ture and pressure sufficient to produce further conversion. The hot oil from the heating coil 66 passes into reaction chamber 16, and the vapors separated in this reaction chamber pass out therefrom through line 1?, controlled by valve 78, into dephlegmator II, where they are subjected to reflux condensation with the vapors from dephlegmator l4 and chamber 38.

If desired, the vapors evolved in reaction chamber 16 can be separately condensed and collected by usual means which, for the sake of simplicity, have not been shown in the diagrammatic drawing. In this case valve 18 on line H is closed and valve 18 is opened on branch line l'i leading to conventional dephlegmating, condensing, and collecting means such as shown in connection with chamber 38. If these vapors are separately recovered, and if reflux condensate is formed during dephlegmation of these vapors, said reflux can be subjected to further treatment or separately collected.

The unvaporized oil from reaction chamber 16 is withdrawn therefrom through line 19, controlled by valve and can be led to storage or elsewhere through line 8|, controlled by valve 82.

Or, said unvaporized oil can be directed through line 83 in which is interposed a pump 84, controlled by valves 85, back into the charging line 3. Pump 84 can be by-passed through line 86, controlled by valve 87.

The conditions of operations maintained on the various parts of the system will be regulated according to the characteristics of the materials treated, and of the products desired. Where the material is more refractory than that from which it originated, the conditions of retreatment will be more severe in temperature and pressure than the conditions of the primary treatment. For instance, if the reflux condensate from the primary treatment is more diflicult to crack than the raw oil which is being charged into the system, it is necessary to increase the temperature and pressure conditions to a point necessary to produce conversion of the reflux condensate. This, if the reflux condensate had been retreated with the raw oil in the primary part of the system, would have caused from the originally treated raw oil the formation of undesirable constituents, such as carbon and gas, while where the reflux condensates are retreated separately as in the hereinbefore explained process, the conditions on the various parts of the system are maintained independently from each other and can be regulated to give the best results in each part of the process and avoid, for instance, overheating and undue formation of coke and gas in the treatment of the original raw oil.

For an illustration of the operation of the process herein described, the heating coil can be maintained under a pressure of 250 pounds and the raw oil can be subjected therein to a temperature. of 850 F., more or less. The reflux condensate formed in the first dephlegmation of the vapors evolved from the raw oil, and passed from dephlegmator l4 through heating coil 33, and the apparatus connected therewith, can be treated in -heating coil 33 under a pressure of, say 350 to 400 pounds at a temperature ofv 900 to 950 F.

The reflux condensate formed by the second dephlegmation of the vapors originated in the treatment of the raw oil in coil 5, and which is passed from dephlegmator I! through heating coil 66, can be treated in said heating coil under a pressure of, say 500 to 600 pounds, more or less, and at a temperature of 1000 F., more or less.

The temperature and pressure maintained on the said heating coil 66 will also depend upon the characteristics of the liquid fractions formed in chamber 38 and the dephlegmator 44, if the latter is used, when said fractions are combined with the reflux condensate from dephlegmator l I for further treatment through heating coil 66.

It is not believed necessary to give further illus trations of the various conditions which can be maintained on the different parts of the system because it is believed that a skilled operator can select said conditions without departing from the scope of the invention, and according to the characteristics of the various products treated in the various parts of the system.

The various valves and pumps shown, allowed to maintain such different pressures, have been described between said various parts of the system. In each conversion zone, the expansion chamber and dephlegmator connected therewith can respectively be maintained under the same pressure as its heating coil, or the dephlegmators can be maintained under a pressure reduced below the pressure of the chamber, or above atmospheric pressure, or it can be reduced to atmospheric pressure. In the same manner, the condensing and collecting parts of each zone can be maintained under the same pressure as the balance of its corresponding zone, or under reduced or raised pressure.

I claim as my invention:

1. A cracking process which comprises subjecting the charging oil to cracking conditions of temperature and pressure and separating vapors therefrom, subjecting the vapors to primary and secondary dephlegmation, thereby forming primary and secondary reflux condensates, cracking the primary reflux condensate under independently controlled cracking conditions of temperature and pressure and separating the same into vapors and unvaporized oil, combining such unvaporized oil with the secondary reflux condensate and cracking the resultant mixture independently of. the charging oil and primary reflux condensate, and fractionating resultant vapors in admixture with the vapors undergoing secondary dephlegmation.

2. A cracking process which comprises heating hydrocarbon oil to cracking temperature under pressure and separating vapors therefrom, dephlegmating the vapors to condense heavier fractions thereof, simultaneously subjecting a lighter oil to more drastic cracking than the first-mentioned oil and separating the same into vapors and unvaporized oil, combining such unvaporized oil with a portion of the reflux condensate formed in said dephlegmation, subjecting the resultant mixture to independently controlled cracking conditions of temperature and pressure and dephlegmating vapors evolved therefrom in admixture with vapors formed in the first mentioned heating step.

3. The process as defined in claim 2 further characterized in that said lighter oil comprises another portion of. the reflux condensate formed in said dephlegmation.

4. A conversion process which comprises fractionating hydrocarbon vapors in successive primary and secondary fractionating zones to form a relatively heavy primary reflux condensate and a lighter secondary reflux condensate, subjecting such primary reflux condensate to cracking conditions of temperature and pressure in a cracking zone and separating resultant products into relatively heavy components and lighter components, simultaneously cracking secondary reflux condensate from said secondary zone under independently controlled cracking conditions of temperature and pressure in a second cracking zone, introducing at least a portion of said heavy components into said second cracking zone for treatment therein in admixture with said secondary reflux condensate, fractionating vapors formed in the second cracking zone in admixture with the first-named vapors undergoing fractionation in said secondary fractionating zone, and finally condensing the vapors uncondensed in said secondary fractionating zone.

5. The process as defined in claim 4 further characterized in that said heavy components introduced to the second cracking zone comprise reflux condensate formed by fractionation of vaporous conversion products from the first-named cracking zone.

6. A conversion process which comprises fractionating hydrocarbon vapors in successive primary and secondary fractionating zones to form a relatively heavy primary reflux condensate and a lighter secondary reflux condensate, subjecting such primary reflux condensate to cracking conditions of temperature and pressure in a cracking zone and separating the same into vapors and residue, simultaneously cracking secondary reflux condensate from said secondary zone under independently controlled cracking conditions of temperature and pressure in a second cracking zone, fractionating the last-named vapors and subjecting resultant reflux condensate to further cracking by introducing it into said second cracking zone for treatment therein in admixture with said secondary reflux condensate,,fractionating vapors formed in the second cracking zone in admixture with the first-named vapors undergoing fractionation in said secondary fractionating zone, and finally. condensing the vapors uncondensed in said secondary fractionating zone.

'7. The process as defined in claim 6 further characterized in that said last-named vapors are fractionated in said secondary fractionating zone.

8. A hydrocarbon oil conversion process which comprises distilling the charging oil in a distilling 3 zone and fractionating the resultant vapors in successive primary and secondary fractionating zones, cracking resultant primary reflux condensate and secondary reflux condensate respectively in a first cracking zone and a second cracking zone under independently controlled cracking conditions of temperature and pressure, introducing vapors formed in both said cracking zones into said secondary fractionating zone for fractionation therein in admixture with the portion of. the first-named vapors undergoing fractionation in this zone whereby insufficiently cracked fractions of the last-named vapors are condensed and supplied with the secondary reflux condensate to said second cracking zone, and

finally condensing the vapors uncondensed in said,

secondary fractionating zone.

9. The process as defined in claim 4 further characterized in that said resultant products from the first-named cracking zone are partially and residual portions thereof introsaid heavy vaporized duced to the second cracking zone as components.

WILLIAM R. HOWARD. 

